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Evidence for an Ax‐adenosine receptor in the guinea‐pig atrium
Author(s) -
Collis M.G.
Publication year - 1983
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1983.tb09381.x
Subject(s) - adenosine , adenosine receptor , chemistry , potency , adenosine a1 receptor , guinea pig , theophylline , medicine , endocrinology , atrium (architecture) , pharmacology , receptor , agonist , biology , biochemistry , in vitro , atrial fibrillation
1 The purpose of this study was to determine whether the adenosine receptor that mediates a decrease in the force of contraction of the guinea‐pig atrium is of the A 1 ‐ or A 2 ‐sub‐type. 2 Concentration‐response curves to adenosine and a number of 5′‐ and N 6 ‐substituted analogues were constructed and the order of potency of the purines was: 5′‐N‐cyclopropylcarboxamide adenosine (NCPCA) = 5′‐N‐ethylcarboxamide adenosine (NECA) >N 6 cyclohexyladenosine (CHA) > L‐N 6 ‐phenylisopropyl adenosine ( l ‐PIA) = 2‐chloroadenosine > adenosine > D‐N 6 ‐phenylisopropyl adenosine ( d ‐PIA). 3 The difference in potency between the stereoisomers d ‐ and l ‐PIA was over 100 fold. 4 The adenosine transport inhibitor, dipyridamole, potentiated submaximal responses to adenosine but had no significant effect on those evoked by the other purines. 5 Theophylline antagonized responses evoked by all purines, and with d ‐PIA revealed a positive inotropic effect that was abolished by atenolol. 6 The results indicate the existence of an adenosine Ai‐receptor in the guinea‐pig atrium.